1. Field of the Invention
This invention relates to fluid handling processes and apparatus. More particularly, this invention relates to a fluid flow device that is suitable for use in liquid-gas applications such as the distribution of cleaning fluids to wash automotive windshield, headlamp and rear windshield surfaces.
2. Description of the Related Art
Automotive windshield, headlamp and rear windshield cleaning applications need an optimum distribution of cleaning fluid spread over the critical areas to be cleaned in order for adequate cleaning to be accomplished, with or without the aid of wiper action. This task of achieving uniform distribution of cleaning fluid has not been easy for a number of reasons, including the complexity and changing nature of such automotive surfaces. Over the years, automotive designs have involved varying shapes, sizes and inclinations of the windshields and headlamps.
Reference may be made to some examples from the prior art devices for such automotive cleaning tasks. These are reported in U.S. Pat. Nos. 5,975,431 to Harita et al., U.S. Pat. No. 6,354,515 to Matsumoto & Tamano, and U.S. Pat. No. 6,082,636 to Yoshida et al. and others that involve various single orifice, washer nozzles that issue steady jets of liquids into gaseous environments. Nozzles such as these all have potential problems with uniformity of the distribution of cleaning fluid since they all have sprays emitted from the nozzles that impinge on limited area of the glass and then depend on the wiper to spread the fluid. In some cases, puddling of fluid can occur and result in wiper blade lifting. In other instances, there may not be enough wetting of the surfaces before a wiper sweeps across the surface to complete the cleaning process. In still other situations, nonuniformity of spray distributions result when the spray does not impact on the targeted areas due to the spray's interactions with the air passing around a moving vehicle.
This situation has been substantially improved in recent years by using several types of spray nozzles that issue spatially oscillating, rather than steady, jets of liquids into gaseous environments. Spray nozzles of this type are referred to herein as being “fluidic” nozzles. The improvements they provide center around the fact that the centerlines of the sprays that issue from them oscillate from side to side so that their sprays wet a much larger surface area than can be wetted by the spray from a non-oscillating, steady jet. See U.S. Pat. Nos. 4,508,267 and 5,749,525 to Stouffer, U.S. Pat. No. 5,971,301 to Stouffer & Heil, U.S. Pat. No. 6,186,409 to Srinath and U.S. Pat. No. 6,253,782 to Raghu.
Such fluidic nozzles have been very successful in a wide variety of cleaning applications, including automotive. This success is due to the nature of the sprays issuing from such nozzles—they are oscillating sprays or jets of fluid that sweep back and forth, and which can cover a wide area of the automotive glass to achieve uniform cleaning fluid distribution and prewetting of the to-be-cleaned surface.
Also, such fluidic nozzles can be engineered to yield some unique capabilities. For example, they can be engineered to yield spray drop distributions that have significantly larger-size, fluid drops than conventional nozzles. These larger size drops allow the targeted areas to be more quickly wetted than with conventional nozzles, providing such fluidic nozzles with improved high-speed, cleaning performance. However when such sprays are aimed higher to compensate for the spray depression occurring at high speeds, overspray over the sides may result. These nozzles can also be engineered to provide sprays having specified, nonuniform fluid droplet distributions (e.g., sprays having a larger percentage of their droplets near the outer edges of the spray's distribution).
U.S. Pat. No. 6,062,491 to Hahn combines two fluid nozzles into a single housing or stem that is mounted in front of an automotive surface to be cleaned. This combination yields two independently-operating, diverging fluid sprays that are reported to be capable of wetting a wider surface area. Such combinations of fluid nozzles into a single housing for cleaning purposes are also seen in U.S. Pat. No. 4,185,777 to Bauer, (see elements 31 and 40 in FIG. 3), U.S. Pat. No. 4,390,128 to Fujikawa (see FIG. 3A), U.S. Pat. No. 4,516,288 to Fizyta (see element 22 in FIG. 1), and U.S. Pat. No. 4,520,961 to Haeber (see FIG. 5).
Experiments with the invention of Hahn using various fluidic nozzles have revealed several problems whose solutions are not disclosed in Hahn's U.S. Pat. No. 6,062,491. These include fluid leakage problems around the fluidic chips that are inserted into automotive housings of the kind that are used to mount single fluidic nozzle for automotive windshield, headlamp and rear windshield cleaning applications. This result is not surprising since it is well known in the fluidic nozzle industry that sealing the housings around such nozzle inserts can be problematic, especially when the sealing task is compounded by having twice as much surface area to seal due to a second chip having been molded into the nozzle insert. Because of the comparatively high fluid pressures desired to be used in such dual, fluidic nozzle configurations, such chips have been actually spit from their housings due to the large pressures built up on the surface of the nozzles.
Thus, despite the prior art, there still exists a continuing need for fluid nozzles that can provide a desired distribution of fluid over larger surface areas.
3. Objects and Advantages
There has been summarized above, rather broadly, the prior art that is related to the present invention in order that the context of the present invention may be better understood and appreciated. In this regard, it is instructive to also consider the objects and advantages of the present invention.
It is an object of the present invention to provide an improved fluidic spray device that utilizes multiple nozzles in a single housing to provide a desired distribution of fluid over a large surface area.
It is another object of the present invention to provide such an improved fluidic spray device without having this device have the magnitude of fluid leakage problems that are currently associated with such devices.
It is yet another object of the present invention to provide such an improved fluidic spray device that is easy to manufacture and install in its required housing.
It is still another object of the present invention to provide such an improved fluidic spray device that is especially well suited for uniformly distributing cleaning fluids to wash automotive windshield, headlamp and rear windshield surfaces.
It is an object of the present invention to provide an improved fluidic spray device that will eliminate the problem of the sprays from current fluidic nozzles being swept over the hoods and the sides of cars that are traveling at high speeds.
These and other objects and advantages of the present invention will become readily apparent as the invention is better understood by reference to the accompanying summary, drawings and the detailed description that follows.